DE19717538C2 - Process for producing a molded part - Google Patents

Description

The present invention relates to a method for manufacturing make a molded part with a base layer and a Top layer, in which the base layer is made of fiber-reinforced Plastics and the cover layer consist of a cover film and the connection between these two layers in one single hot pressing is produced.

DE 38 38 199 A1 describes a method for coating SMC, BMC and DMC materials with foils disclosed. The Connection between the carrier layer and the cover film by rinsing the edges of the top layer with SMC Material from the carrier layer durable and robust.

DE 41 01 106 A1 describes a method for producing lami Niert molded parts disclosed in which in a two-step first drive a molding made of thermoplastic material is injection molded before it is fully cured is covered with cover layer material and in a second press step is connected to this.

Furthermore, DE 42 24 667 A1 discloses a method for Production of multi-layer wall coverings, in which the for Formation of the carrier part and the decorative part used plant fabrics are placed one after the other in a heatable form, in which they are then pressed together. Preferably should first a carrier layer is pressed and in one second press stroke, a decorative layer can be applied. The a characteristic innovation of this publication is the Use of a temperature block layer, preferably made of Cotton fiber fleece or foam to make temperature sensitive Surface materials before the necessary high temperatures to protect in the backing layer.  

DE 40 29 910 A1 describes an automatic device Production of large-area molded parts from thermosetting press mass revealed.

A process sequence conceivable with this machine is suitable not for the production of two-layer molded parts which the top layer of high quality decorative materials should exist.

The article in Kunststoffe, 85 (1995), 3, pages 319 to 321 describes the use of natural fibers to manufacture fibers reinforced plastic components and offers no process description for the production of multi-layer molded parts.

However, a disadvantage of the known manufacturing processes is that the problem has not yet been solved satisfactorily simple press method with only one press stroke to use to connect a cover layer material with a carrier layer, a carrier layer to be produced uniformly injection-moldable BMC or SMC plastics and dekora tive top layer made of different textiles or wood veneers can exist. Furthermore, it would be for the manufacturer development process cheap, but not yet realized if at the same time with the only press stroke plunge edges on the Press tool itself the top layer material, for example Veneers to which the dimensions of the base layer can be cut.

Another method is known from EP 0 325 690 B1. In the method shown there, it is possible to Base layer and a top veneer layer in a single press punching process to a workpiece with an appealing upper shape surface. At least the base layer preferably exists partly made of wood or one of several individual layers layered base veneer. The connection between base position and veneer layer is in the known method by Made of synthetic resin adhesive. With the known method he  you keep veneer workpieces with good surface properties and with a high torsional stiffness.

A disadvantage of the known method, however, is that the Structure of the layer structure of the desired deck layer and the intended application got to. It is also necessary to use fasteners which the molded part for example for the interior cladding Vehicle is attached, subsequently to the pressed To attach molded part.

It is therefore the object of the present invention This necessitates two separate press strokes to circumvent that the material of the carrier layer from that of decorative top layer through the additionally introduced Adhesive film is physically delimited on the one hand, so that Cover layer material not of liquid during the pressing process components of the support layer can be contaminated to others a precisely fitting adhesive connection between the carrier and the top layer is produced.

This object is achieved by the features of claim 1.

The production of a multi-layer molded part in only one Pressing process brings a simplified production process yourself. The method according to the invention offers in production run the rationalization advantage, a uniform Base layer made of SMC and BMC material with an adhesive film thermosetting type based on sodium or Recycled paper with a urea melamine resin Mixture impregnated as a carrier for various high-quality decorative layers, such as veneers, to be able to use.

In the present invention, the top layer is used alone through the inserted adhesive film with the components of the Trä Gerschicht connected, with plunge edges of the mold be set to the deck during the single press stroke layer material fits perfectly to the dimensions of the carrier layer  tailored.

For the SMC mats used to build up the base layer are flat structures, which consist of unsaturated Polyester resins with glass filaments exist. Are preferred LP (Low Profile) high-polymer components with high shrinkage retired setting as part of the SMC mat hen, other components are additives such as release agents and Storage stabilizers and mineral fillers in any color setting. BMC stands for "bulk molding compound". A material made from this can be used in a quasi liquid state be injected into the tool.

In the method according to the invention, heat and Print until the hardenable compo is completely hardened be maintained.

The pressing is preferably carried out at one temperature between 120 ° C and 160 ° C, the temperature is particularly preferred temperature range between 140 ° C and 160 ° C.

Depending on the general conditions, such as the thickness of the The molded part and the temperature used are different Require periods to harden the hardenable materials such. The time period for curing therefore varies between there. 30 seconds and 5 minutes, but is preferred between 2 and 3 minutes.

Veneers are preferably used as the top layer.

These advantageously have a thickness between 0.1 milli meters and 0.9 millimeters, the thickness is often between 0.4 Millimeters and 0.6 millimeters.

Decorative veneers, for example real wood, are preferred veneers used.  

It can also be provided that as an additional Interlayer a non-woven or blind veneer in the layer composite is introduced. This improves the Inherent rigidity, resulting in better handling of the Decorative veneers, especially when it comes to real wood veneers acts, results.

The introduction of thermosetting resins, such as Phenolic resin or similar bring special advantages.

A particular advantage of the method according to the invention is that fasteners, for example on the Back or on the side edges of the molded part immediately the molding process can be molded or embedded.

The production of the molded parts is advantageously in suitable presses or tools.

Natural and / or artificial work can be used as a top layer fabrics and / or combinations of the types of materials mentioned be used.

It is also possible to use different decoration materials, such as fabric, textile, synthetic leather, leather, plastic, paper, paper-like fabrics, metals and / or combinations of use these materials.

The method proves to be particularly advantageous if the Top layer a coating facing away from the visible surface has a tearing of the cover layer during the pressing process prevented.

There can also be various top layer materials besides to be arranged one above the other.

The molded part remains in until it has completely hardened its shape, so that an unproblematic removal of the  finished workpiece can be done. The press tool is then immediately available for the next production process. Due to the favorable flow properties of the melted Materials, it is possible to attach fasteners directly to form or embed during the pressing process. The procedure parameters such as time, temperature and pressure during the pressing process can be adjusted so that the molten material too can flow into small mold cavity areas, thereby forming of fastening devices is possible. Special advantages when using SMC mats continue to result from their good shelf life. Can be wound on rolls prepared SMC mats stored for up to six months become. Furthermore, the method is characterized in that with short cycle times molded parts of the highest  Strength can be produced because the respective pre Given fiber reinforcement structures during the pressing process remain intact.

Using the drawings, the inventive method in following are exemplified.

Fig. 1 shows a press punch in a sectional view perpendicular to its main plane in the open state with inserted SMC mat and top layer before the pressing process.

FIG. 2 shows the press punching tool from FIG. 1 during the pressing process.

Fig. 1 shows a pressing and punching tool 2 with a movable die 4 and a counter die 6. The punch 4 has a punch surface 8 , the counter tool surface 10 . The punching tool 4 and the counter tool 6 lie opposite one another with the punching surface 8 and the counter surface 10 . Between the punching surface 8 and the counter surface 10 , an intermediate space 12 is shown in the open state of the press punch 2 shown in FIG. 1, which allows the insertion of an SMC mat 18 and a cover layer 20 . The counterpart tool 6 has on its counter surface 10 recesses 14 , 16 , the importance of which is discussed in connection with FIG .

In Fig. 2 the same press punch tool is shown during the Preßvor gear. In this state, SMC mat 18 and cover layer 20 are pressed by pressing the punching surface 8 of the punching tool 4 against the counter surface 10 of the counter tool 6 to form a molded part 22 . The ver liquid material during the pressing process has also penetrated into the recesses 14 , 16 of the counter surface in the counter tool, so that fastening devices 24 , 26 , in this case on the back of the molded part, are formed during the pressing process.

In the case of using BMC material, the press punch tool 2 is equipped with a sprue through which the liquid material is introduced into the tool. Otherwise, the method using BMC material proves to be just as advantageous as when using SMC mats, in particular with regard to the variability of the materials otherwise used, the manageability of the finished, hardened molded part and the possibility of immediately forming fastening devices.

Reference list

2nd

Press punch tool

4th

Punching tool

6

Counter tool

8th

Punching surface

10th

Counter surface

12th

Space

14

,

16

Recess

18th

SMC mat

20th

Top layer

22

Molding

24th

,

26

Fastening device

Claims (21)

1. A method for producing a molded part with a base layer and a cover layer in a single pressing process in the heat, in which the base layer consists of fiber-reinforced plastics, characterized in that the connection between the base and the cover layer introduced by an additional Adhesive film is generated. 2. The method according to claim 1, characterized in that a thermosetting Adhesive film based on soda or Recycled papers with a urea-melamine resin Ge are mixed impregnated. 3. The method according to claim 1 or 2, characterized in that as a base layer one or more SMC mat (s) or through BMC material injected into the mold will be used. 4. The method according to any one of the preceding claims, characterized characterized in that the pressing process until complete hardening of the curable materials continues. 5. The method according to claim 4, characterized in that the pressing process takes place at a temperature of 120 ° C to 160 ° finds. 6. The method according to claim 4, characterized in that the pressing process at a temperature of 140 ° C to 160 ° C takes place. 7. The method according to any one of the preceding claims, characterized characterized in that the pressing process over a period between between 0.5 and 5 minutes.   8. The method according to any one of the preceding claims, characterized characterized in that the pressing process over a period between is maintained for 2 and 3 minutes. 9. The method according to any one of the preceding claims, characterized characterized in that the cover layer is formed from a veneer becomes. 10. The method according to claim 9, characterized in that Veneer with a thickness of 0.1 to 0.9 millimeters is used becomes. 11. The method according to claim 9, characterized in that Veneer with a thickness of 0.4 to 0.6 millimeters is used becomes. 12. The method according to any one of claims 9 to 11, characterized ge indicates that a decorative veneer is used. 13. The method according to claim 12, characterized in that a real wood veneer is used. 14. The method according to any one of the preceding claims, characterized characterized in that a fleece or Blind veneer is introduced. 15. The method according to any one of the preceding claims, characterized characterized in that thermosetting resins, such as phenolic resins or the like are introduced. 16. The method according to any one of the preceding claims, characterized characterized in that fasteners during the pressing process be shaped or embedded. 17. The method according to any one of the preceding claims, characterized characterized in that the top layer is natural and / or artificial  Liche materials and / or combinations of the above Ma types of materials can be used. 18. The method according to any one of the preceding claims, characterized characterized in that various decorative materials, such as Fabric, textile, synthetic leather, leather, plastic, paper, paper Similar substances, metals and / or combinations of the mentioned materials can be used. 19. The method according to any one of the preceding claims, characterized characterized in that the top layer abge the visible surface has facing coating that tears in the top layer prevented during the pressing process. 20. The method according to any one of the preceding claims, characterized characterized in that different decorative layer materials ne be provided side by side. 21. The method according to any one of the preceding claims, characterized characterized in that the cover layer and the base layer at Pressing process in the edge and edge area by means of plunge edges any protrusions are removed precisely.